Composition comprising a vinyl chloride resin and 3, 5-dimethyl delta 4:5-cyclohexene 1, 2-di-2-ethylhexyl dicarboxylate



Patented Nov. 13, 1951 UNITED STATES COMPOSITION COMPRISING A VINY L CHLO- RIDE RESIN AND 3,5 DIMETHYL A4:5- CYCLOHEXENE LZ-DI-Z-E'IHYLHEXYL DI- CARBOXYLA TE George L. Fraser, Springfield, Mesa, asslgnor to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware No Drawing. Application September 25, 1948, Serial No. 51,310

\ ticular object of the invention is to provide plasticized vinyl chloride polymer compositions.

These and other objects are accomplished according to this invention by providing as plasticizing and softening agents for high molecular weight materials, alkyl esters of 3:5 dimethyl A4:5 cyclohexene 1:2 dicarboxylic acid in which the alkyl groups contain 6-12 carbon atoms. These esters may be represented by the following general formula:

wherein R and R are alkyl groups having 6-12 carbon atoms. It is found that plasticized compositions containing the above esters are characterized by unusual flexibility, coupled with high plasticizer retentivity, both at ordinary temperatures and at elevated temperatures.

The following examples are illustrative of the present invention, but are not to be construed as limitative thereof. Where parts are mentioned, they are parts by weight.

Example I 100 parts of polyvinyl chloride are mixed with 50 parts of the 3:5 dimethyl A415 cyclohexene 1:2 di-2-ethyl hexyl di-carboxylate on milling rolls maintained at a temperature of 300 F., to form a homogeneous composition. From this composition there are pressed sheets 0.020 inch in thickness. These sheets are found to be clear and substantially colorless. They are characterized by a high degree of flexibility over a wide range of temperatures, and are found to suffer relatively low weight loss on long standing and at elevated temperatures. Furthermore, these sheets are found to have a tensile strength of 2710 pounds per square inch, an ultimate elonga- 2 tion of 450% and a modulus at 100% elongation of 1450 pounds per square inch.

Example II Example I is repeated except that 100 parts of the ester are used. The product has generally the same properties as the product of Example I but is somewhat more flexible.

Example III 100 parts of cellulose acetate (55% acetyl groups) and 50 parts of 3:5 dimethyl A4z5 cyclohexene 1:2 di-Z-ethyl hexyl dicarboxylate are dissolved in 1000 parts of acetone. The resulting solution is flowed onto a glass plate and the acetone allowed to evaporate therefrom. The resulting films are clear and colorless. In addition, they are found to be flexible and somewhat elastic.

so Example IV Example 111 is repeated except that the amount of plastlcizer is increased to 100'parts. The resulting films are clear and colorless and considerably more flexible than the films prepared as in Example III.

Example V 100 parts of polystyrene and 50 parts of 3:5 dimethyl A4z5 cyclohexene 1:2 di-2-ethyi hexyl dicarboxylate are dissolved in 1000 parts of toluene. Films prepared from the resulting solution after evaporation of the solvent are found to be clear and colorless and to possess a considerable degree of flexibility.

Example VI Example V is repeated except that the amount of plasticizer is increased to 100 parts. Films prepared from the product are found to be even 40 more flexible than the films in Example V. Moreover, this increased flexibility is attained without sacrifice as regards clarity and lack of color.

Example VII 100 parts of polyvinyl butyral acetal resin to evaporate therefrom. The dried films are clear and colorless and unusually flexible and elastic.

Example VIII Example VII is repeated except that the 9 amount of plasticizer is increased to parts.

3 Films prepared from the product as in the Preceding examples are colorless and clear. In addition, they are somewhat more flexible and elastic than the films in Example VII. The films are also characterized by high strength characteristics.

The ester plasticizers of the invention may be prepared by esterifying the adduct of 2-methy1 pentadiene 1:3 and maleic anhydride. The following is an example of the preparation of the 3:5 dimethyl A4z5 cyclohexane 1:2 di-2-ethyl hexyl dicarboxylate.

Example A The adduct of 2-methyl pentadiene 1:3 and maleic anhydride is formed by mixing the two components in equi-molecular proportions at room temperature and allowing the mixture to stand until the exothermic reaction subsides. To the resulting adduct are added 2 mols of 2-ethyl hexanol for every mol of adduct and the resulting mixture is heated at 150 C. until the theoretical amount of water is evolved. The resulting product is purified by fractional distillation to yield a colorless liquid having a boiling point of 185 C. at an absolute pressure of 2 millimeters of mercury, and a refractive index of N 1.4638. This ester which is new in the art has the following formula:

In place of the 2-ethyl hexyl ester of 3:5 dimethyl A425 cyclohexene 1:2 dicarboxylic acid, other esters in which the alkyl groups have 6-12 carbon atoms may be used in plasticizing high molecular weight materials. Thus, the hexyl, heptyl, nonyl, decyl, undecyl and dodecyl esters may be prepared by the method of Ex ample A by substituting the corresponding alcohols for the 2-ethyl hexanol and may be used in providing plasticizing compositions having unique characteristics. The alkyl groups in these esters may have straight or branched chains.

In preparing the esters of the invention, considerable latitude in reaction conditions is permissible. Thus, substantially varying reaction temperatures may be used, e. g., from 125 C. to 250 C. However, in order to avoid an unduly lengthy reaction, temperatures of 150 C. or higher are usually preferred. In order to expedite the reaction, small amounts of such catalysts may be used, if desired, as for example, sulfuric acid, phosphoric acid, p-toluene sulfonic acid, camphor sulfonic acid and the like.

The new esters of the invention are useful as plasticizers and softeners for high molecular weight materials generally. Examples of such materials include cellulose esters, e. g., cellulose acetate, cellulose propionate, cellulose nitrate; cellulose ethers, e. g., ethyl cellulose, methyl cellulose, chlorinated rubber; synthetic resins such as polymerized vinyl aromatic materials, e. g., polystyrene; polyvinyl esters, e. g., polyvinyl chloride, polyvinyl acetate, polyvinylidene chloride, as Well as copolymers of these and other pclymerizable materials; polyvinyl acetal resins, e. g., polyvinyl formal, polyvinyl acetal dehyde acetal, polyvinyl butyral, etc.

The amount of plasticizer or softener which is incorporated in the plasticizable material depends upon the particular characteristics which it is desired to impart to the plasticizable material, as well as on the compatibility of the plasticizer in the composition. In the case of the plasticizers of the invention, it is usually desirable to incorporate at least 5 parts in every 100 parts of plasticizable material and generally, from 25-75 parts yield the most advantageous properties. However, the amount used should not exceed its compatibility in the composition. Mixtures of the esters of the invention with other plasticizers may be desirable in certain instances. Typical of well known plasticizers which may be used in conjunction with the esters of the invention are dioctyl phthalate, tricresyl phosphate, dibutyl phthalate, etc.

In particular, it is found that the esters of the invention are especially valuable in admixture with vinyl chloride-containing polymers. Thus, in place of polyvinyl chloride, the esters of the invention may be used in conjunction with various copolymers of vinyl chloride and other unsaturated materials copolymerizable therewith. Examples of such copolymers include copolymers of vinyl chloride with such materials as vinylidene chloride, vinyl esters of carboxylic acids, for example, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate; esters of unsaturated acids. for example, alkyl acrylates, such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate and the corresponding esters of methacrylic acid; vinyl aromatic compounds, for example, styrene, ortho-chloro-styrene, para-chloro-styrene, 2,5-dichloro-styrene, 2,4-dichloro-styrene, para-ethyl styrene, vinyl naphthalene, alpha-methyl styrene; dienes, such as butadiene, chloroprene; amides, such as acrylic acid amide, acrylic acid am'lide; nitriles, such as acrylic acid nitrile; esters of ace-unsaturated carboxylic acids, for example, the methyl, ethyl, propyl, butyl, amyl, hexyl, heptyl, octyl, allyl, methallyl and phenyl esters of maleic, crotonic, itaconic, fumaric acids and the like. Usually, at least 10% of the copolymer is vinyl chloride and the class of copolymers in which a predominant portion, i. e., more than 50% by weight of the copolymer is made from vinyl chloride, represents a preferred class of polymers to be plasticized according to the invention.

A particularly preferred embodiment of the invention comprises the plasticization of polymers prepared by copolymerizing vinyl chloride and an ester of an rip-unsaturated dicarboxylic acid such as diethyl maleate, in which 530 parts by weight of the dicarboxylic acid ester are used for every 95-70 parts by weight of vinyl chloride. Among the preferred esters of a,fl-unsaturated d1- carboxylic acids are the alkyl esters in which the alkyl group contains 1-8 carbon atoms.

It is obvious that many variations may be made in the processes and products of this invention without departing from the spirit and scope thereof as defined in the appended claims.

vWhat is claimed is:

1. A composition comprising a vinyl chloride- 5 containing polymer and a compatible amount of 3:5 dimethyl A4z5 cyclohexene 1:2 di-2-ethyl hexyl dicarboxylate.

2. A composition as defined in claim 1 in which the polymer is polyvinyl chloride.

3. A composition as deflnedin claim 1 in which the polymer is a copolymer of vinyl chloride and a vinyl ester of a saturated fatty acid. 1

5 4. A composition as defined in claim 3 in which the polymer is a copolymer of vinyl chloride and REFERENCES CITED The following reteren es are of record in the file of this patent:

UNITED STATES PATENTS vinyl acetate. Number Name Date 5. A composition as defined in claim 1 in which 2,221,035 swan 12, 1940 the polymer is a copolymer of vinyl chloride and 5 2,262,002 Hopff et 1941 an ester of an u,fl-unsaturated dicarboxylic acid. 2,275,383 Soday a 3, 1942 6. A composition as defined in claim 5 in which 2,275,385 soday 3, 1 4 the polymer is a, copolymer of vinyl chloride and 3 1 Gresham 10, 9 djethy] maleat 2,311,259 Staff 813 3,1. Feb. 16, 1943 GEORGE FRASER, 10 2, 4,8 Soday Sept. 18, 1945 2,445,627 Morris et a1 July 20, 1948 

1. A COMPOSITION COMPRISING A VINYL CHLORIDECONTAINING POLYMER AND A COMPATIBLE AMOUNT OF 3:5 DIMETHYL *4:5 CYCLOHEXENE 1:2 DI-2-ETHYL HEXYL DICARBOXYLATE. 